<template>
  <div class="back-top" @click="backTop">
    <i class="arrow"></i>
  </div>
</template>

<script>
  import { mapMutations } from 'vuex'
    export default {
        methods: {
          ...mapMutations([
            'UPDATE_TOPBAR_BLOCK'
          ]),
          backTop(){
            window.scrollTo({ top: 0 })
            this.UPDATE_TOPBAR_BLOCK('ture')
          }
        }
    }
</script>

<style lang="scss" scoped>
.back-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 40px;
  height: 40px;
  line-height: 40px;
  text-align: center;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 5px rgba(0,0,0,.05);
  cursor: pointer;
  .arrow {
    display: inline-block;
    width: 5px;
    height: 0px;
    border: 5px solid #999;
    border-top: 5px solid transparent;
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    margin-bottom: 3px;
  }
}
</style>
